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691.
The tropical Indo-West Pacific is the biogeographic region with the highest diversity of marine shallow water species, with
its centre in the Indo-Malay Archipelago. However, due to its high endemism, the Red Sea is also considered as an important
centre of evolution. Currently, not much is known about exchange among the Red Sea, Indian Ocean and West Pacific, as well
as connectivity within the Indo-Malay Archipelago, even though such information is important to illuminate ecological and
evolutionary processes that shape marine biodiversity in these regions. In addition, the inference of connectivity among populations
is important for conservation. This study aims to test the hypothesis that the Indo-Malay Archipelago and the Red Sea are
important centres of evolution by studying the genetic population structure of the giant clam Tridacna maxima. This study is based on a 484-bp fragment of the cytochrome c oxidase I gene from 211 individuals collected at 14 localities in the Indo-West Pacific to infer lineage diversification
and gene flow as a measure for connectivity. The analysis showed a significant genetic differentiation among sample sites
in the Indo-West Pacific (Φst = 0.74, P < 0.001) and across the Indo-Malay Archipelago (Φst = 0.72, P < 0.001), indicating restricted gene flow. Hierarchical AMOVA revealed the highest fixation index (Φct = 0.8, P < 0.001) when sample sites were assigned to the following regions: (1) Red Sea, (2) Indian Ocean and Java Sea, (3) Indonesian
throughflow and seas in the East of Sulawesi, and (4) Western Pacific. Geological history as well as oceanography are important
factors that shape the genetic structure of T. maxima in the Indo-Malay Archipelago and Red Sea. The observed deep evolutionary lineages might include cryptic species and this
result supports the notion that the Indo-Malay Archipelago and the Red Sea are important centres of evolution.
Communicated by Biology Editor Dr. Ruth Gates 相似文献
692.
Fishes of the genus Gobiodon are habitat specialists by their association with Acropora corals. Little is known about the parameters that define host coral quality for these fishes, in particular their breeding
pairs. Data were collected in the northern Red Sea using 10 × 1-m belt transects in different reefs and zones. Gobiid density
was highly correlated with coral density over all sites and zones, and the more specialized goby species preferred coral species
that are less vulnerable to environmental stress. Moreover, the occupation rate of corals by goby breeding pairs significantly
increased with colony size and decreased with partial mortality of colonies. Logistic regression showed that both coral size
(being most important) and partial mortality are key factors influencing the occupation by breeding pairs. This study provides
the first evidence that breeding pairs of coral-associated gobiids have more advanced habitat requirements than con-specifics
in other social states. As coral reefs are threatened worldwide and habitat loss and degradation increase, this information
will help predict the potential effects on those reef fishes obligatorily associated with live corals. 相似文献
693.
Y.-J. Luo L.-H. Wang W.-N. U. Chen S.-E. Peng J. T.-C. Tzen Y.-Y. Hsiao H.-J. Huang L.-S. Fang C.-S. Chen 《Coral reefs (Online)》2009,28(1):289-301
Cnidaria–dinoflagellate endosymbiosis is the phenomenon of autotrophic symbionts living inside the gastrodermal cells of their
animal hosts. The molecular mechanism that regulates this association remains unclear. Using quantitative microscopy, we now
provide evidence that the dynamic lipid changes in gastrodermal “lipid bodies” (LBs) reflect the symbiotic status of the host
cell and its symbiont in the hermatypic coral Euphyllia glabrescens. By dual-emission ratiometric imaging with a solvatochromic fluorescent probe, Nile red (9-diethylamino-5H-benzo[α]phenoxazine-5-one),
we showed that the in situ distribution of polar versus neutral lipids in LBs in living gastrodermal cells and symbionts can
be analyzed. The ratio of Nile red fluorescence at red (R) versus green (G) wavelength region (i.e., R/G ratio) correlated
with the relative molar ratio of polar (P) versus neutral (NP) lipids (i.e., P/NP ratio). The R/G ratio in host LBs increased
after bleaching, indicating a decrease in neutral lipid accumulation in gastrodermal cells. On the other hand, neutral lipid
accumulation inside the symbiont LBs resulted in gradual decreases of the R/G ratio as a result of bleaching. In comparison
with the bleaching event, there was no relative lipid concentration change in host LBs under continual light or dark treatments
as shown by insignificant R/G ratio shift. Patterns of R/G ratio shift in symbiont LBs were also different between corals
undergoing bleaching and continual light/dark treatment. In the latter, there was little lipid accumulation in symbionts,
with no resulting R/G ratio decrease. These results, demonstrating that the symbiotic status positively correlated with morphological
and compositional changes of lipid bodies, not only highlight the pivotal role of LBs, but also implicate an involvement of
lipid trafficking in regulating the endosymbiosis. 相似文献
694.
Habitat loss due to land reclamation often occurs in sandy coral reef shore zones. The giant sea anemone Stichodactyla gigantea, which harbors the false clown anemonefish Amphiprion ocellaris, both of which are potentially flagship species, inhabit these places. To assess habitat quality for S. gigantea, we examined correlative associations between the number and the body size of S. gigantea and the amount of habitat types in fine-scale seascape composition quantified from an enlarged section of a high-resolution
(1/2,500) color aerial photograph of the shallow shore zone of Shiraho Reef, Ishigaki Island, Japan. This study confirmed
that anemones were most abundant at the edges of dense seagrass beds characterized by shallow sandy bottoms, rock beds, and
sparse seagrass beds, while they were less abundant in coral patch reefs. However, anemones inhabiting coral patch reefs were
significantly larger and their rate of disappearance over 3 years was lower than those inhabiting other habitats. This suggests
that coral patch reefs may be more suitable habitats supporting larger animals and greater persistence of S. gigantea. The visual census techniques applied here, combined with aerial photography and image-analysis software, may be useful as
a simple analytical tool for local assessment of suitable habitats for relatively small-bodied marine fauna in shallow-water
seascapes. 相似文献
695.
Peter F. Cowman David R. Bellwood Lynne van Herwerden 《Molecular phylogenetics and evolution》2009,52(3):621-631
We estimated ages of divergence between major labrid tribes and the timing of the evolution of trophic novelty. Sequence data for 101 labrid taxa and 14 outgroups consisting of two mitochondrial gene regions (12s, 16s), and two nuclear protein-coding genes (RAG2, TMO4c4), a combined 2567 bp of sequence, were examined using novel maximum likelihood, maximum parsimony and mixed model Bayesian inference methods. These analyses yielded well supported trees consistent with published phylogenies. Bayesian inference using five fossil calibration points estimated the minimum ages of lineages. With origins in the late Cretaceous to early tertiary, the family diversified quickly with both major lineages (hypsigenyine and julidine) present at approximately 62.7 Ma, shortly after the K/T boundary. All lineages leading to major tribes were in place by the beginning of the Miocene (23 Ma) with most diversification in extant lineages occurring within the Miocene. Optimisation of trophic information onto the chronogram revealed multiple origins of novel feeding modes with two distinct periods of innovation. The Palaeocene/Eocene saw the origins of feeding modes that are well represented in other families: gastropod feeders, piscivores and browsing herbivores. A wave of innovation in the Oligocene/Miocene resulted in specialized feeding modes, rarely seen in other groups: coral feeding, foraminifera feeding and fish cleaning. There is little evidence of a general relationship between trophic specialization and species diversity. The current trophic diversity of the Labridae is a result of the accumulation of feeding modes dating back to the K/T boundary at 65 Ma, with all major feeding modes on present day reefs already in place 7.5 million years ago. 相似文献
696.
Investigation of the life history of corals is hampered by an inability to identify early recruits. In this study, the pattern
of formation and morphology of the juvenile skeletons of three laboratory-reared pocilloporids, Seriatopora hystrix, Stylophora pistillata and Pocillopora damicornis, were compared to determine whether they could be reliably distinguished. The pattern of skeleton formation, including the
origin and structure of the septa, columella and corallite wall was similar in all species. Following the completion of the
primary corallite wall after 4–5 days, these species could be identified by differences in the diameter of the primary corallite.
The mean diameter (±SE) of each species differed markedly: S. hystrix 400 ± 2.7 μm, range 325–450 μm; S. pistillata 505 ± 3.5 μm, range 400–550 μm; P. damicornis 697 ± 7.5 μm, range 492–885 μm. Values for the primary corallite diameter overlapped in only 3% of samples, demonstrating
the potential utility of this feature as a tool for classifying recruits obtained from the field.
Accepted: 4 January 2000 相似文献
697.
This study investigates the nature and components of annual luminescent banding in massive Porites coral skeletons, with a view to refining the technique for using this banding to reconstruct past environmental conditions.
Three-dimensional excitation-emission-matrix spectroscopy and optical fibre beam delivery have been used to investigate the
luminescence properties of the bright and dull bands of solid coral. Six characteristic excitation/emission peaks have been
identified: 280/450–600, 340/450, 370/470, 390/485, 420/505 and 450/530 nm. The first peak corresponds to protein-type fluorescence.
The others are characteristic of humic acid luminescence. The difference in luminescence intensity between bright and dull
bands has been quantified and characterised spectroscopically. The luminescence of the bright bands is up to 25% more intense
than their neighbouring dull bands with the greatest increase in relative intensity in the long wavelength emission region,
between 500 and 600 nm. The contribution of long-lived phosphorescence to the total luminescence intensity has been determined
by time-resolved measurements on the 100 ms timescale. Both bright and dull bands show long-lived phosphorescence with decay
times up to 1.5 s. This phosphorescence accounts for about 10% of the total luminescence intensity of bright bands. The difference
in phosphorescence intensity between bright and dull bands is substantially greater than the difference in total luminescence
intensity: the phosphorescence of bright bands is up to twice as intense as that of dull bands. This suggests that phosphorescence
plays an important role in defining luminescent banding in coral. Furthermore, the large observable difference in phosphorescence
between bright and dull bands indicates that measurement of phosphorescence profiles across growth bands in corals may prove
to be a more sensitive indicator of past environmental conditions than measurements of total luminescence.
Received: 18 March 1999 / Accepted: 20 December 1999 相似文献
698.
Spatial patterns in abundance of a damselfish reflect availability of suitable habitat 总被引:9,自引:0,他引:9
For species with metapopulation structures, variation in abundance among patches can arise from variation in the input rate
of colonists. For reef fishes, variability in larval supply frequently is invoked as a major determinant of spatial patterns.
We examined the extent to which spatial variation in the amount of suitable habitat predicted variation in the abundance of
the damselfish Dascyllus aruanus, an abundant planktivore that occupies live, branched coral throughout the Indo-Pacific. Reef surveys established that size,
branching structure and location (proximity to sand) of the coral colonies together determined the ”suitability” of microhabitats
for different ontogenetic stages of D. aruanus. Once these criteria were known, patterns of habitat use were quantified within lagoons of five Pacific islands. Availability
of suitable habitat generally was an excellent predictor of density, and patterns were qualitatively consistent at several
spatial scales, including among different lagoons on the same island, among different islands and between the central (French
Polynesia and Rarotonga) and western (Great Barrier Reef, Australia) South Pacific. A field experiment that varied the amount
of suitable coral among local plots indicated that habitat for settlers accounted for almost all of the spatial variation
in the number of D. aruanus that settled at that location, suggesting that spatial patterns of abundance can be established at settlement without spatial
variation in larval supply. Surveys of four other species of reef-associated fish revealed that a substantial fraction of
their spatial variation in density also was explained by availability of suitable reef habitat, suggesting that habitat may
be a prevalent determinant of spatial patterns. The results underscore the critical need to identify accurately the resource
requirements of different species and life stages when evaluating causes of spatial variation in abundance of reef fishes.
Received: 18 May 1999 / Accepted: 9 January 1999 相似文献
699.
The supply of larvae is a major determinant of population and community structure in coral reef fishes. However, spatial and
temporal variation in condition (i.e. quality) of potential recruits, as well as their density (i.e. quantity), may influence
survival and growth of juveniles. We conducted an experiment to test whether recent feeding history could affect growth, condition
and post-recruitment survival in a Caribbean damselfish, Stegastes partitus. Fish were collected soon after settlement, and fed either low or high rations in aquaria for 7 days. Fish fed the high ration
grew faster in aquaria and were in a better condition (higher total lipids and Fulton’s condition factor) at the end of the
feeding period. Subsequently, we released 50 fish in 25 pairs (one fish subjected to low rations, the other to high rations)
on a Bahamian coral reef and monitored survival for 10 days. Survivorship of high-ration fish was double that of low-ration
fish (80 vs 40% over 10 days). However, low-ration fish that survived 10 days were of similar condition and grew at similar
rates to high-ration fish, suggesting that short-term ration differences may not persist in surviving fish. Laboratory experiments
showed that low-ration fish were taken by piscivorous fishes before high-ration fish, indicating that differential predation
may account for survival differences. This study highlights the potential of feeding history and condition to affect the relationship
between patterns of larval arrival at reefs, and subsequent juvenile and adult population densities.
Received: 1 March 1999 / Accepted: 15 July 1999 相似文献
700.
Summary The Upper Rhaetian coral limestone of Adnet, southeast of Salzburg Austria has been repeatedly referred to as one of the most
spectacular examples of an ancient ‘autochthonous’ coral reef structure. The ‘Tropfbruch’ quarry is probably the best outcrop
for interpreting the distributional patterns of biotic successions and communities of a late Triassic patch reef. Our study
is based on the interpretation of a) outcrop photographs, b) reef maps resulting from quadrat transects, and c) the analysis
of quantitative data describing the distribution and frequency of reef organisms and sediment. A new methodological approach
(combination of reef mapping and photo-transects) is used to obtain quantitative field data which can be compared in greater
detail with data from modern coral reefs investigated by corresponding quantitative surveys.
Three unconformities and three well-defined ‘reef growth stages’ reflecting the vertical and lateral development of the reef
structure were differrentiated using transects:
Stage 1, representing the reef growth optimum, is characterized by laterally differentiated coral reef knobs with corals in
growth position. Criteria supporting this interpretation are the extraordinary size of the corals, their preservation in situ
and the great thickness of this interval. The massive coralPamiroseris grew under higher energy conditions at the rim of the reef knob, whereas branchingRetiophyllia colonies preferred less agitated water in the center. Vertical changes are reflected by an increase in frequency of the dasycladacean
algaDiplopora adnetensis and by the decreasing size ofRetiophyllia. These sedimentological and biological criteria together with the unconformity above indicate a fall in the sea level as
a major control mechanism.
Stage 2, separated from stage 1 by an unconformity caused by partial subaerial exposure and karstification, is characterized
by vertically stacked coral successions with diverse reef debris. Facies heterogeneity is reflected by differences in the
diversity, taphonomy and packing density of reef-building organisms as well as by differences in sediment input from the platform.
Water depths and accommodation space were lower, therefore minor sea level fluctuations had a stronger effect on the biotic
composition. The high percentage of coral debris and corals reworked by storms and the increase in the input of platform sediment
led to a reduction of reef growth.
Stage 3, again separated at the base by an unconformity associated with karstification, is characterized by bioclastic sediments
with isolated reefbuilders forming a level-bottom community. The distribution of different coral morphotypes suggests that
sea level fluctuations were not the only controlling factor. Variations in the substrate were caused by differences in the
input of platform sediment.
The three-step development seen in Adnet documents the response of low-diverse coral associations to variations caused by
small-scale sea level changes, storm activity and sedimentation. The vertical changes in reef community structures correspond
to a sequence of ‘allogenic replacements’.
The Adnet reef structure should not be regarded as a general model of Alpine Upper Rhaetian reefs, because of the particular
setting of the patch reef. Only the ‘capping beds’ of the Upper Rhaetian Reef Limestone of the Steinplatte exhibit criteria
similar to Adnet.
Potential modern analogues of features seen in the coral communities of Adnet are the internal structure of theRetiophyllia thickets, the key role of branching corals within the communities, the scattered distribution and low and even diversity
of corals subsequent to breaks in settlement, segration patterns of corals indicating ‘contact avoidance’, toppling of large
coral colonies by intensive boring, and decreasing coral coverage from deeper and sheltered settings to more shallower water
depths. 相似文献